DC9/MD80 FAMILY

[Yan104]

Dear Tonytale,

I honestly appreciate your technical descriptions of DC9 , that I was anable to find anywhere else on the Web ! ... I printed technical and historical records of this beautiful family of aircrafts , but none describes me as precisely each parts of this plane. It seems to me that the DC8 has a much broader fuselage than the DC9 , as it was designed for transatlantic flights , and the tradition among manufacturers is that the big carriers haved 3 lanes . I have had a sketch of the configuration of the passengers cabin of the DC9 -10 , and I saw that there were five rows of seats in front, three on the right side, and two on the left , a little as regional aircrafts of today ERJ 170/190 and ATR72 ! ... I do not know if this configuration has been stored on the MD80 . Have you had the opportunity to do maintenance on them? Have you discovered the other aircrafts in the family, such as 20 and 30 series ?
I do not know if you've noticed it , if necessary look at a close-up photo of the nose of the DC8 , it has two slots on each side of his nose, which is not found on the DC9 . What can it fit ? Is it hatches for the weather radar ? If so, where do we have then moved the sensors on the DC9 ?


I have a little trouble understanding the technical terms translated from English to French ! ... What is the E and E compartment ? I think I have guessed that this is about the avionics of the aircraft. So this compartment was located just after the forward baggage compartment , and just before the door of the front landing gear ( also called in French nose wheel ) , is that right? I guess these equipments were totally different from those of Glass Cockpits with digital units and circuits : what it was exactly like devices, this was hydraulic or pneumatic sensors, probes or other ?

I'm terribly annoyed that the redundancy of the flight control cables were installed in the same location as the main controls , on the floor . And more to the main electrical circuits ... So we can better understand why the loss of all control circuits, electrical as mechanical was devastating for the DC9- 32 of the Valujet... I even believe that the control cables of reactors power also passed through the floor because those of No.1 engine was disrupted , Kandy(the girl captain) was no longer able to modulate his power ... Do you think engineers of MDD could organize the distribution of cable redundancy otherwise, were there other possibilities?

It did not seem to me that the DC9 was equipped with an APU ! ... How is it that there was no exhaust nozzle at the tail? How did it work compared to other gas turbines on other planes?
So if I understand your explanation , air conditioning and pressurization systems were neighbors of the APU ? Is valve pressurization was stood back and forward fuselage ?

I know that the wet parts of an aircraft such as toilets are sources of internal corrosion. But why the pressure bulkhead , supposed to be waterproof, producing it from moisture ? ! ... Was it after each cycle of depressurization in the descent of the plane ? Are there already had technical problems here ? What was the cycle of visits of this very sensitive part of the aircraft, and which elements were to replace frequently?